The sensory modalities of normal human adults and some other animals clearly operate in concert as an integrated system. For most adaptive behavior, information received by vision, for example, is coordinated with information from touch (cross-modal perception, CMP), even though the events at the end organs are distinctly different. As an extension of our previous CMP research with chimpanzees and the work of others with humans, we propose a more detailed analysis of the phenomena. Specifically, we will study tactual/visual inter- and intramodal perception as influenced by and/or interacting with simple unidimensional stimulus properties, complex objects (both quantifiable and scalable), methods of testing, extensive training, and varying memory requirements between the two events of a perceptual task. We are particularly interested in the perceptual characteristics of the hand and its activity in information extraction. We propose to develop a "haptic" taxonomy which will be studied in relation to stimulus features, object classes, extent of training and sequence of stimulus presentation. Despite the presumed importance of the hand in hominid evolution, its role as a perceptual "organ" has been little studied in phyletic perspective. Research with humans strongly suggests the superiority of visual as opposed to tactual perception. However, the contributin of language to this difference is unknown. Use of the alinguistic chimpanzee may aid in clarification of this and other issues in related human research. Further relevance to human perception and its deficits is discussed in the text.